[PATCH][Precise] platform/x86: Apple gmux driver

Seth Forshee seth.forshee at canonical.com
Thu Mar 1 15:49:53 UTC 2012

I realize we're past feature freeze, so maybe this is SRU material. This
patch has been submitted upstream, and I've been waiting for Matthew
Garrett's feedback but so far have received none. This either means he
has no objections or that he hasn't had time to look at it, likely the
latter as he's been quite busy lately. I do expect to get this upstream
in its current form, with few or no changes, hopefully in 3.4.

This is a new driver to support the gmux device found on hybrid-graphics
Apple laptops. The gmux controls switching of the integrated panel
between the two GPUs and screen brightness. Currently the driver only
supports the backlight functionality. The display muxing is only
supported under native EFI booting, which requires patching the kernel
for other reasons so isn't of much concern at this time. Backlight
control is of concern however, as many machines with the gmux have no
other method of adjusting the screen brightness.

As this is a standalone driver, there's no impact on any other code or
any machines other than MacBooks with the gmux device. I put out a call
for testing on the Ubuntu Mactel Community mailing list, which did not
get an overwhelming response but did result in several different MacBook
models getting tested. The results are available at [1].

Thoughts? Should we go ahead and pick this up, or wait for it to get


[1] https://wiki.ubuntu.com/Kernel/AppleGmuxBacklight

Seth Forshee (1):
  platform/x86: Add driver for Apple gmux device

 drivers/platform/x86/Kconfig      |   10 ++
 drivers/platform/x86/Makefile     |    1 +
 drivers/platform/x86/apple-gmux.c |  228 +++++++++++++++++++++++++++++++++++++
 3 files changed, 239 insertions(+), 0 deletions(-)
 create mode 100644 drivers/platform/x86/apple-gmux.c

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